/***************************************************************************
 * Bytecode Viewer (BCV) - Java & Android Reverse Engineering Suite        *
 * Copyright (C) 2014 Konloch - Konloch.com / BytecodeViewer.com           *
 *                                                                         *
 * This program is free software: you can redistribute it and/or modify    *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation, either version 3 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 ***************************************************************************/

package the.bytecode.club.bytecodeviewer.resources;

import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipFile;
import org.apache.commons.io.FilenameUtils;
import org.objectweb.asm.tree.ClassNode;
import the.bytecode.club.bytecodeviewer.api.ASMUtil;
import the.bytecode.club.bytecodeviewer.util.FileHeaderUtils;
import the.bytecode.club.bytecodeviewer.util.MiscUtils;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

/**
 * @author Konloch
 * @since 7/10/2021
 */
public class ResourceContainerImporter
{
    private final ResourceContainer container;

    public ResourceContainerImporter(ResourceContainer container)
    {
        this.container = container;
    }

    /**
     * Return the linked container
     */
    public ResourceContainer getContainer()
    {
        return container;
    }

    /**
     * Start importing the container file as a file
     */
    public ResourceContainerImporter importAsFile() throws IOException
    {
        try (FileInputStream fis = new FileInputStream(container.file))
        {
            return addUnknownFile(container.file.getName(), fis, false);
        }
    }

    /**
     * Start importing the container file as a zip archive
     */
    public ResourceContainerImporter importAsZip() throws IOException
    {
        container.resourceClasses.clear();
        container.resourceClassBytes.clear();
        container.resourceFiles.clear();

        try
        {
            //attempt to import using Java ZipInputStream
            return importZipInputStream(false);
        }
        catch (Throwable t)
        {
            try
            {
                //fallback to apache commons ZipFile
                return importApacheZipFile(false);
            }
            catch (Throwable t1)
            {
                t1.addSuppressed(t);
                throw t1;
            }
        }
    }

    /**
     * Adds an unknown resource to the container
     * This will sort the file and start the file-specific adding process
     */
    public ResourceContainerImporter addUnknownFile(String name, InputStream stream, boolean classesOnly) throws IOException
    {
        //TODO remove this .class check and just look for cafebabe
        if (name.endsWith(".class"))
            return addClassResource(name, stream);
        else if (!classesOnly)
            return addResource(name, stream);

        return this;
    }

    /**
     * Adds a class resource to the container
     */
    public ResourceContainerImporter addClassResource(String name, InputStream stream) throws IOException
    {
        byte[] bytes = MiscUtils.getBytes(stream);
        if (FileHeaderUtils.doesFileHeaderMatch(bytes, FileHeaderUtils.JAVA_CLASS_FILE_HEADER))
        {
            try
            {
                final ClassNode cn = ASMUtil.bytesToNode(bytes);

                //classes are copied into memory twice
                ClassNode existingNode = container.resourceClasses.put(FilenameUtils.removeExtension(name), cn);
                container.resourceClassBytes.put(name, bytes);
                if (existingNode != null)
                {
                    //TODO prompt to ask the user if they would like to overwrite the resource conflict
                    // or solve it automatically by creating a new resource container for each conflict (means no editing)

                    System.err.println("WARNING: Resource Conflict: " + name);
                    System.err.println("Suggested Fix: Contact Konloch to add support for resource conflicts");
                }
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }
        else
        {
            System.err.println(container.file + ">" + name + ": Header does not start with CAFEBABE, ignoring.");
        }

        return this;
    }

    /**
     * Adds a file resource to the container
     */
    public ResourceContainerImporter addResource(String name, InputStream stream) throws IOException
    {
        byte[] bytes = MiscUtils.getBytes(stream);
        container.resourceFiles.put(name, bytes);
        return this;
    }

    /**
     * Imports resources from zip archives using ZipInputStream
     */
    private ResourceContainerImporter importZipInputStream(boolean classesOnly) throws IOException
    {
        try (ZipInputStream jis = new ZipInputStream(new FileInputStream(container.file)))
        {
            ZipEntry entry;
            while ((entry = jis.getNextEntry()) != null)
            {
                final String name = entry.getName();

                //skip directories
                if (entry.isDirectory())
                    continue;

                addUnknownFile(name, jis, classesOnly);
                jis.closeEntry();
            }

            return this;
        }
    }

    /**
     * Imports resources from zip archives using Apache ZipFile
     * <p>
     * TODO if this ever fails: import Sun's jarsigner code from JDK 7, re-sign the jar to rebuild the CRC,
     *      should also rebuild the archive byte offsets
     */
    private ResourceContainerImporter importApacheZipFile(boolean classesOnly) throws IOException
    {
        try (ZipFile zipFile = new ZipFile(container.file))
        {
            Enumeration<? extends ZipArchiveEntry> entries = zipFile.getEntries();
            while (entries.hasMoreElements())
            {
                ZipArchiveEntry entry = entries.nextElement();
                String name = entry.getName();

                if (entry.isDirectory())
                    continue;

                try (InputStream in = zipFile.getInputStream(entry))
                {
                    addUnknownFile(name, in, classesOnly);
                }
            }
        }

        return this;
    }
}
